Among methods for treating teeth, there are about two million patients who require regeneration of the alveolar bone. There is a great need for the dissemination of a safe, convenient treatment method. Current treatments exist in the form of a method of collecting and embedding bone from the pelvis of the patient, and a recently developed method of using bone marrow cells collecting and cultivating from the patient. However, both of these methods present drawbacks in the areas of patient safety, cost, and the like.
Teeth are comprised of enamel (the outer layer portion of a tooth), dentin, dental pulp, cementum, and periodontal ligament. Most regions are comprised of enamel and dentin. The enamel is comprised of 95 percent apatite (calcium phosphate) and 5 percent water. The dentin is comprised of 70 percent apatite, 20 percent collagen, and 10 percent water. The dentin is known to contain trace quantities of useful proteins and the like for stimulating osteoinduction.
Accordingly, the present inventors considered that teeth that are unneeded by the patient's own (extracted teeth) could be recycled. As an example, they developed a method by which such teeth were pulverized, the granular pulverized product was embedded, and the alveolar bone was regenerated. The present inventors have reported the use of a commercially available manual device to pulverize extracted teeth, the obtaining of samples by demineralizing and washing with hydrochloric acid, and the embedding samples beneath the subcutaneous tissues of the back region in rats and nude mice, resulting in osteoinduction and cartilage induction. (1) Daisuke SATO, Masaru MURATA, Tomoya SASAKI, Toshiyuki AKAZAWA, Makoto ARISUE, Osteoinduction by human demineralized dentin/recombinant human BMP-2 composite implant, Journal of the Japanese Society of Oral Implantology, 15, 403-411 (2002) (Nonpatent Reference 1). (2) Masaru MURATA, Daisuke SATO, Toshiyuki AKAZAWA, Toshio TAIRA, Tomoya SASAKI, Makoto ARISUE, Osteoinduction and cartilage induction by human demineralized dentin granules in nude mice, Journal of Hard Tissue Biology, 11 (3), 110-114 (2004) (Nonpatent Reference 2). Further, the present inventors have already achieved treatment results in eight patients using this method. Recently, extracted teeth have been placed in frozen storage (for example, in a tooth bank) and later transplanted (delayed transplant treatment). However, to-date, there has been almost no use of extracted teeth in regeneration, and no method of placing extracted teeth in a state permitting their use in regeneration has been established.
Japanese Unexamined Patent Publication (KOKAI) Heisei No. 9-308640 (Patent Reference 1) discloses the use of at least a portion of the root portion of an extracted tooth as a mold to produce an artificial root. However, it does not describe the use of the extracted tooth itself in regeneration.    [Nonpatent Reference 1] Daisuke SATO, Masaru MURATA, Tomoya SASAKI, Toshiyuki AKAZAWA, Makoto ARISUE, Osteoinduction by human demineralized dentin/recombinant human BMP-2 composite implant, Journal of the Japanese Society of Oral Implantology, 15, 403-411 (2002).    [Nonpatent Reference 2] Masaru MURATA, Daisuke SATO, Toshiyuki AKAZAWA, Toshio TAIRA, Tomoya SASAKI, Makoto ARISUE, Osteoinduction and cartilage induction by human demineralized dentin granules in nude mice, Journal of Hard Tissue Biology, 11 (3), 110-114 (2004).    [Patent Reference 1] Japanese Unexamined Patent Publication (KOKAI) Heisei No. 9-308640.